I am one of the very rare breeds that has a fully active system, 6 Jeff Rowland monoblocks running Klipschorns with an Accuphase F-25V electronic crossover in front of the amplifiers, and the passive crossovers taken out of the speakers. It sounds absolutely phenomenal, like nothing else out there. I've been in the business 35 years and have yet to meet anyone (in home audio at least) who has done something similar. It's done all the time in pro audio, yet nobody talks about it for home use. It's widely known that an actively amplified setup simply IS better than any passively crossed over speaker, since the dividing is done before the amplifier, each amplifier only amplifies a certain frequency range, and then the output of the amplifier is connected directly to an individual driver with nothing in between. If anyone has such a setup, is interested in learning more about one, or wants to throw in their 2 cents, please do! It's about time we did talk about this, and I can't believe in all these years more companies haven't actively (pun intended) embraced this type of setup. Also, if anyone has crossover cards for an F-25V crossover, please let me know!!!
In my own case, I just never did, at the time I was considering the idea, get past the extra cost and complexity (especially since I use a DAC, which have required an extra A-to-D and D-to-A conversion). And I'd be curious to know what kind of volume-control solution you came up with...I feel I eventually would likely have found one, but for me I knew it would neither be easy nor cheap...especially if resistor-based solutions (or better) were the goal, which they were for me. In the end I managed to get around some the performance disadvantages (actually in some quite unorthodox ways, as it turned out) of sticking to passive crossovers and a single amp per channel, but of course not completely so, as I'm sure you can imagine. Another thing, by way of the Behringer DCX that I was considering, was being able to digitally time align the drivers in my 3-way towers (no sub). I actually may still, at some point, rebuild my speaker cabinets so as to be able to do this physically, when I have the money and have figured out the last of the of the how-to's. But, after some point of looking into the idea of multi amping before your post, I did reach the realization that the potential for performance gain is unquestionably a real and valid thing. And I also can't say why it hasn't been discussed more than it has either, but I agree with you that just because manufacturers have dropped the ball on embracing the concept doesn't mean the rest of us have to - so kudos for being willing to help mark the trail and for starting this thread and I hope for everyone's sake others will join in. Good post. Regards. John
Great to see a reply so soon after posting. Yes it is more complex, and costly, so it's not for everyone. But not really...if for example (and I know this isn't a good one) people are buying $100,000 speakers to be driven by a $50,000 monster power amp, it makes far more sense to not buy the crossover assembly within the cabinet (there's a lot of expense there), but to buy 2 or 3 smaller amplifiers and an electronic crossover, as long as the quality is on par with what you're giving up. And yes you need more cabling. But the sound will be NIGHT AND DAY better. Not having a bunch of coils, capacitors and resistors between the output of the amplifier and the driver itself, it HAS to be better.
I have the Esoteric stack, P-01/2x D-01/G-0Rb. It has a variable output and it drives the crossover directly, no preamp at all. Not all DACs can do that, and some people swear by a preamp. My philosophy is if the DAC has a proper drive stage to begin with, you don't need one, unless you need input switching or a volume control. If you do need a volume control and/or input switching, Goldpoint makes what I consider the best passive preamp available, and it's cheap($500)! I have the SA-1X balanced version, and it's so simple, yet sounds so transparent, it's like there's nothing there (not using it at the moment). And yes it's a stepped attenuator, just what you're looking for. They sell them direct, and the RCA version will be even less, like $300. OK, back to crossovers. I used an Audio Control Richter Scale for a while when I was just starting, and the Behringer is along similar lines. It will certainly get you into the world of active, and it's worth trying just to see what active does, but honestly, you won't be happy with it in the long run. It's cheap, so you won't lose much if you resell it, but it's pretty low-end. The question of course, is what do you buy that's better? Bryston has one, never tried it. There's just not much around. Accuphase makes one, but they're all digital now, and pretty expensive. My crossover runs in the analog domain, so there's no extra A/D and D/A conversion, but they haven't built them since 2001! There's just no demand. As far as time-aligning goes, I have quite a bit of experience with that. You are FAR better off to physically move the drivers so they're time aligned, than trying digital delay. It sounds WAY better if you can build the speakers time-aligned in the first place. I've found over the years, that digital anything - crossovers, delays, filters, equalisation...just doesn't sound nearly as good for some reason, as doing it in the analog domain. And thanks, I really wanted to start this thread as it's something that CAN be done, in the real world, with real budgets. The only people that I know of that have ever done anything like this in the consumer world is Linn. It's okay, it has quite the cult following, but it's not my cup of tea. Keep writing, as you make progress. Thanks John!
I'm currently working on a JBL fully active system. I'm building a pair of 4345 but with 2206 mid-bass, and 2441/2309/2310 mid-range. I have 3 Acoustat TNT200 amps and one TNT120. I will use 2 of them in mono for bass, 1 for mid-bass and the 120 for the 2441s. I'll need another one for the 2405s. I'm about to have the cabs built by a reputable builder. I'm thinking of building in a qick-change capability to use the 2441s in reverse as direct radiators with just the 2310 in front. That way I can use these monsters in a medium size room. A couple of DCX2496 should do the trick but I'm wondering about a Marchand 4-way or maybe Mini-DSP. I'm leaning toward the Marchand analog vs. digital, though. What are your thoughts or experience in this regard?
After using actively multi-amped systems for years(pro); I started doing it at home, in 1981. By then: I had my own shoppe building, modding and repairing pro and home audio speaker systems and electronics. My first home system used KEF drivers and Rogers LS3-5A crossovers(all matched) in the mains, an active X-over, built with DeCoursey Lab boards, and KEF B-139's, in sealed enclosures. Being a Hafler dealer; I used all highly modded Hafler(SS) gear, at the time. Sold that system, and built some 10" driver(Nestorovics), 8' tapered, folded transmission-line woofers, bought a Dahlquist DQ-LP1 filter and a pair of Acoustat Mod III's. Again- using heavily modded Hafler gear for power. Still have the same TL bottom end(now housing SEAS L26ROY D1001's), a modded Hafler TransNova 9505, but using a modded TacT RCS 2.2X, Magnepan MG12qr's and Modded Cary SLM-100's. I'd love to go bigger on the mains, BUT- a costly divorce lost me a lot of listening area(in SQ FT).
My TNTs were just rebuilt/modified by Roy Esposito in Florida. He added fully balanced mode and mono capability. I've not had any prior experience with these amps. He was instrumental in developing the circuit being an engineer at Acoustat back then so he knows what's possible. All I can say is they are the fastest, most musical amps I've yet experienced. They are 'visceral'. A term that has not come to mind in describing an amp till now. However, Andy Szabo, another former engineer at Acoustat, uses modified 9505s also. He say's they are a significant improvement over the TNTs. I've not had any experience with this amp. But he's comparing to the stock TNT. Is there anything you can tell me in comparison? I need another amp for the 2405s or maybe something else for the bottom end.
Never have used the TNT amps. I started with modded DH-500's, and gave my last one(used to drive the 10's) to my son, a number of years back, when I bought the TransNova. I stopped using SS to drive my mains, decades ago, so- I can't really give an opinion of what the 9505 would sound like in that app. If you like the TNT's; I hardly believe you could go wrong with a 9505. Jim Strickland(another Acoustat alumnus)supposedly had much to do with it's design. Did the mods to your TNT's include replacing the rectifiers with HEXFREDs(or Schottkys)? Really cleans and opens the upper registers. Just something easy/basic/inexpensive and well worth the effort. Behringer X-overs work in cheap pro apps, but- I wouldn't use one for home audio(except for expermentation). I guess there are some out there, that mod them though.
Dealer post disclaimer.....not trying to sell here but I have been selling completely active systems with time and phase alignment software which is integrated into the xover matrix for 12 individual drivers and separate amplifiers for each driver, for the last 10 years. Our latest incarnation is also completely wireless, have a peek. http://www.my-hiend.com/vbb/showthread.php?6971-Goldmund-Apologue-Anniversary
Csontos, I'd go with the DCX2496es personally, but it's your call. I've heard them, and they're not terrible, the soundstage is just somewhat flat and boring, and somewhat trebly. It's just the nature of the beast, being built in China with small power supplies, inexpensive op-amps, etc., but you can start replacing parts if you want. The Marchand looks a little too "garage made" for me, although it probably sounds okay. You do want accurate gain control and crossover points, left to right and woofer to tweeter, and the pots seem like they don't have very tight tolerances, so you'll do a lot of tweaking by ear. By the way all, as of the fiscal end of this year in Japan, which happens to be 9/20, Accuphase is dumping all parts for my analog crossover, so if I want any x-over modules I gotta get them now. Found out in just the nick of time. They've built it since 2001, but since then all their new models operate in the digital domain. Yes they're infinitely adjustable with no extra modules, but the down side is you go D/A out from the CD player, through a preamp to the crossover, which then re-converts A/D, does it's processing, then converts D/A once again. Supposedly the converters are pretty high end, but I still have a problem with 3 stages of numbers to sound, sound to numbers, and sound to numbers conversion. The battle continues...
Accuphase has built some excellent gear, over the years. I wouldn't hesitate to try their new X-over for a moment. Room Correction/Time Alignment and high/low-pass filtering in the digital domain can be VERY rewarding, IF done right. I eschewed digital anything(in home), for many years. Then I got stuck with an acoustic nightmare of a listening room, that demanded correction. I tried the Tact and found VERY little downside(especially after extensive power supply mods). The benefits over the modded DQ-LP1(as transparent as it's passive high-pass filter was), far outweighed any slight downside. But then; I'm only using one crossover point(250Hz/10th order).
Why would you encourage me to go with something flat, boring, and somewhat trebly? I'm somewhat baffled. The Marchand has a good reputation and following. In any case, I'm interested in top notch components.
Csontos, I'm not encouraging you to go with anything in particular. The Behringer can be modded pretty easily, with much better op-amps, power supply, etc. to make it WAY better than it ships out of the factory. I'm sorry, I don't know much about the Marchand, I'd never heard of it before this. I'm just not much on equipment with point-to-point wiring, that's all. There's an Accuphase F-25 on Ebay right now, if I needed one and I had the cash, that's what I'd go with. Just an opinion.
Sorry Mustang, for the 3 threads. This website isn't particularily sophisticated, and I didn't know at the time I'd started 3 of them. More than happy to carry on where others have, and let the other 2 die.
Rodman, I too, would love to try the Accuphase DF-55. It's infinitely flexible, so other than perhaps software updates from time to time, it would be a set-and-forget unit, and likely you'd never sell it, nor be able to easily. And, unfortunately, it lists for $22,000. For that money, I gotta try before I buy. Even though there is one for sale here for a steal ($9000), virtually brand new in the box, I just don't like all the D/A and A/D conversion that will go on with an analog input. I'm sure it's really good conversion, but it's just occuring too many times, IMO. If you have a digital source with attenuation, then it should sound pretty damn awesome. You are, of course, now listening to an Accuphase DAC (actually many of them), they're pretty good I'm sure, if you like Delta-Sigma DACs. Personally, I think Delta-Sigma DACs, even multiple ones in parallel, have a particular sound that simply can't match the R2R Burr-Browns, no matter what power supply or surrounding circuitry you throw at them. In any case, the guy who has one for sale has an audio store, but can't even hook it up, he doesn't have the speakers necessary to do so. So even if you go there, you can't listen to it, and it's likely the only one in the country opened up that one could theoretically listen to. You spends your money and you takes your chances.
I couldn't agree more, about trying before buying(at that price). When my Tact RCS 2.2X was new; it cost around $5000.00(not as deep a bite) and I knew it was easily modded. Like the Accuphase; it performs A/D and D/A, for both my sources and I am just giving up a VERY slight bit of transparency, compared to the one DynamiCap polypropylene hi-pass capacitor, per channel, in the modded Dahlquist DQ-LP1 I was using. That is far outweighed by the benefits of the active HI/LO filtering, room correction & time alignment that it performs. One would reasonably expect the Accuphase unit(at it's price point) to far exceed my Tact's performance, right out of the box(unmodded). The A/D converter operates at 24 bit/172.4 kHz & the digital input; at up to 192kHz, which should result in virtually no loss. Is there no way to audition that one for $9K, or any other of the same model, anywhere?
Speaker and amplifier designers are invested in the status quo. The proof is that there is no real push to go in the active direction from the equipment designers, even though the results would be superior to what they now produce.
I own the TAD Reference One's, which I biamp passively with the help of a DEQX HDP4. When I approached Andrew Jones for guidance in bypassing the internal crossovers in the TAD's, he gave me the cold shoulder (to put it politely).
I think the best kept secret in high end audio is how horrible internal crossovers are. I am running 2 Magtechs into Sanders Stats via a digital crossover and the sound (to me) is pretty incredible. I don't usually hear that kind of sound coming from a box with a crossover inside.
This has been on my radar for a long time, but for the time being have chosen to get my system to a higher level - I was indeed just starting. I exchanged with Rodman about 3 years ago on this. But technically it makes so much sense, I keep coming back to it.
Taking the opportunity that so many active-ampers are looking at this: please recommend biamp-friendly speakers in the $5-6k range, used ok. I now have a McIntosh MC275 amp and B&W 804S speakers (and 2 active subs). I would be using the MC275 to drive mid/trebble on L&R and would add a SS amp to drive the bass, but taking out the crossovers in the 804S can't be easily done without "damaging" them. Or should I go DIY? I built my subs and am pretty handy...
My sources are all digital coming through a DAC, and have considered the Marchand and DEQ, but lately there seem to be better digital level solutions.
Disconnecting would do it, but getting the cables to the drivers is non-trivial. Maybe I'm missing something, but I envision removing at least the backplate where the speaker cables connect to, so to get those cables right to the drivers.
On second thought, I guess I could by-pass the internal crossover with wires from the speaker connection bolts to the drivers and keep aesthetics as they are...interesting!
While putting some components together for a system my mind tells me to go the actice route. Mind you, I've not had anything since my MCintosh 275s, JBL Pyramids and Winn Strain Guage cartridge in the 80s. So now for starters it's a Clearaudio Maestro cart w/ BAT VK P10 SE.and Zesto Leto pre. Jim Smith (Get Better Sound) lives nearby so he's a resourse. My question is: If I tri-amp or bi-amp a set of Salk Soundscape 12s how do I get the right amps? Jim says in his book that for coherence identical amps are best. If I use 200-300 watts on the bottom end do I need the same for the mid-highs? On the other hand, Dennis Murphy crossovers in the Salks are nothing to sneeze at. I have a pair of Mcintosh MC 60s tube amps being reworked by DeWick. How do I match amps for coherence?
Yes - if you want loud and clean at the same time, it is the best way to go. I have Mackie HR624mk2 monitors - internally biamped with 100w for the woofers and 40w for the tweeters - and a Velodyne powered subwoofer. Tri-amped! When I started fooling around with stereo 40 years ago, I never would have expected to have a tri-amp setup. My current setup is much more dynamic than the B&Ws with the 400 watt amp I had before.
I recently upgraded my front cabinets with 3-way stereo active crossovers, new tweeters and mid range drivers. My front end is a Proceed transport, AVP2+6, AMP5 and Lexicon LX-7. The SEA Millennium tweeters and SEAS 8 woven CURV mid bass drivers use the 125 watt AMP5, and the original 15 bass driver the 250 watt Lexicon.
Active crossovers greatly unleashed the drivers clearest musicality, plus, they seemed to remove problems I thought were upstream. The ACs separate bass, mid, and tweeter volume controllers are the cleanest tone controls Ive ever used to correct poor recordings. The Cello Palette owners manual has a good reference on how to adjust high end tone controls. The SEAS Millennium tweets and the 8 woven CURV woofer-mid is a seamless dynamic combo. Their active XOs are set at 300 and 2K.